This prototype of the Super Game Boy is perhaps more interesting because of the unique board it is on, rather than the ROM image itself. The ROM image is exactly the same as the second revision of the Super Game Boy (1.1), except five bytes in the header are different. Four of those bytes are the internal checksum, while the other one (0x7FDB) is the revision number, which was not switched to "1" in the prototype. The EPROM chip has a date of March 23, 1994 on it. The label also says version 1.0, which could mean that this chip was reused from an earlier revision of the Super Game Boy.